During off-pump coronary artery bypass grafting (OPCAB) which allows complete revascularization through a median sternotomy, revascularization of the lateral and posterior walls requires the verticalization of the heart, which may cause haemodynamic disturbance. This concern has stimulated the development of circulatory support with mini-pumps. Initially, these pumps were designed for the right side of the heart, which was found to be the main contributor to haemodynamic instability under experimental conditions. The three types of mini-pumps that have been developed so far - two for the right side of the heart and one for both sides - are reviewed as well as a new concept of integrated cardiopulmonary bypass (CPB) circuit with reduced surface and priming volume. However, with increasing experience and improved methods of exposition, OPCAB has become a procedure that can be performed without support in the majority of the cases. Nevertheless, the concept of miniaturization and the possibility to insert these devices through a peripheral access has opened the way to new indications, mainly short-term circulatory support for acute heart failure. This development is welcome in a field where available devices are invasive and plagued with a heavy morbidity.